The protests started on 25 April after the ruling party nominated Nkurunziza to run again in elections set for June. Burundi's constitution states a president can run for only two five-year terms. Nkurunziza maintains he can run for a third term because Parliament elected him for his first term, rather than the general public.

Many of the photos taken in Bujumbura over the past few days show protesters wearing bizarre home-made masks – from simple balaclavas and scarves to elaborate headgear made of branches and leaves.

Phil Moore, a photojournalist covering the protests for AFP, says: "It appears to me to be more of a question of style than of masking their identity. I can't help but wonder how much of the visual appearance of these protest movements – not just in Burundi, but worldwide – is influenced by how people see other protests on television, or in print. Theatrics play an important role in activism, and capturing the world's attention."

A youth wearing grass and leaves around his face protests against President Pierre Nkurunziza's decision to run for a third termGoran Tomasevic/ReutersA protester wears a mask made from a leaf in the Cibitoke neighbourhood of BujumburaPhil Moore/AFPA protester wearing headgear made of plants takes part in a demonstration against President Pierre NkurunzizaGoran Tomasevic/ReutersA protester smokes while wearing a maskGoran Tomasevic/ReutersA protester wears a skull mask, presumably to hide his identityGoran Tomasevic/ReutersA masked protester takes part in a protest against President Pierre Nkurunziza's decision to run for a third termGoran Tomasevic/ReutersBurundian youths salute as they demonstrate against the president's bid for a third term in BujumburaSimon Maina/AFP

Some of the protesters were pictured brandishing a dead bird. Moore says this is a reference to the ruling CNDD-FDD party's emblem: an eagle.

Protesters brandish a dead bird as they chant anti-government slogans during demonstrations against the decision to allow President Pierre Nkurunziza to run for a third five-year term in office, in BujumburaThomas Mukoya/ReutersA protester holds up a dead owl to mock the ruling party whose emblem is an eagleGoran Tomasevic/Reuters

Other protesters have taken to covering their faces with soot. Some have theorised that this "blacking up" could be racially motivated, as Hutus are believed to have darker skins than Tutsis.

However, Fulvio Beltrami, a journalist based in east Africa, believes Burundians have overcome ethnic tensions over the years. He says the protest is political, and this is shown by the fact that demonstrators are both Tutsi "and also Hutu who feel betrayed by their party".

A protester with his face smeared with soot stands in the Musaga neighbourhood of BujumburaPhil Moore/AFPA protester with his face blackened with soot participates in the demonstrationsThomas Mukoya/ReutersA demonstrator dressed in leaves and holding bottles filled with stones stands at the edge of a protest in the Musaga neighbourhood of BujumburaPhil Moore/AFP